diff --git a/litellm/constants.py b/litellm/constants.py
index 12749a0fce0..02413ee97ab 100644
--- a/litellm/constants.py
+++ b/litellm/constants.py
@@ -603,7 +603,9 @@ LOGGING_EXECUTOR_MAX_THREADS: Final = get_env_int("LOGGING_EXECUTOR_MAX_THREADS"
 LOGGING_EXECUTOR_MAX_PENDING_TASKS: Final = get_env_int("LOGGING_EXECUTOR_MAX_PENDING_TASKS", 10_000)
 LOGGING_EXECUTOR_DROPPED_TASK_LOG_INTERVAL_SECONDS: Final = 30.0
 AWS_SIGNING_MAX_THREADS: Final = 16
-PROMPT_INJECTION_HEURISTICS_MAX_THREADS: Final = 4
+PROMPT_INJECTION_HEURISTICS_MAX_THREADS: Final = get_env_int(
+    "PROMPT_INJECTION_HEURISTICS_MAX_THREADS", os.cpu_count() or 1
+)
 DD_TRACER_STREAMING_CHUNK_YIELD_RESOURCE: Final = os.getenv(
     "DD_TRACER_STREAMING_CHUNK_YIELD_RESOURCE", "streaming.chunk.yield"
 )
diff --git a/tests/test_litellm/proxy/hooks/test_prompt_injection_detection.py b/tests/test_litellm/proxy/hooks/test_prompt_injection_detection.py
index f6016971357..b189ee740fe 100644
--- a/tests/test_litellm/proxy/hooks/test_prompt_injection_detection.py
+++ b/tests/test_litellm/proxy/hooks/test_prompt_injection_detection.py
@@ -1,4 +1,6 @@
 import asyncio
+import importlib
+import os
 import time
 from concurrent.futures import ThreadPoolExecutor
 
@@ -152,6 +154,19 @@ async def test_heuristics_check_does_not_occupy_default_executor():
     assert unrelated_work_wait < scan_wall / 4
 
 
+@pytest.mark.parametrize(
+    ("configured", "expected"),
+    [("3", 3), ("not-an-int", os.cpu_count() or 1)],
+)
+def test_heuristics_thread_count_config_is_honoured(monkeypatch: pytest.MonkeyPatch, configured: str, expected: int):
+    monkeypatch.setenv("PROMPT_INJECTION_HEURISTICS_MAX_THREADS", configured)
+    try:
+        assert importlib.reload(litellm.constants).PROMPT_INJECTION_HEURISTICS_MAX_THREADS == expected
+    finally:
+        monkeypatch.delenv("PROMPT_INJECTION_HEURISTICS_MAX_THREADS")
+        importlib.reload(litellm.constants)
+
+
 @pytest.mark.asyncio
 async def test_moderation_hook_rejects_unsafe_llm_verdict():
     detector = _moderation_detector(verdict="UNSAFE")